MoO₂@C modified separator as an interlayer for high performance lithium-sulfur batteries

Lithium-sulfur batteries have attracted much attention as a promising next-generation energy storage system due to their high theoretical specific capacity and energy density. However, lithium-sulfur batteries are still facing some problems that hinder their large-scale commercial application. High conductivity molybdenum dioxide coated with carbon composite (MoO₂@C) were introduced to coat the separator to study its application in lithium sulfur batteries. Molybdenum dioxide coated with carbon composite nanoparticles were synthesized by hydrothermal method and high-temperature calcination and then was coated on the separator with acetylene black. The coating layer can take advantage of the synergetic effect of physical barrier and chemical adsorption to reduce the loss of active substances. The electrochemical performance of the battery has been improved by applying MoO₂@C in lithium-sulfur separator. The first discharge specific capacity is 917 mA h g^-1 under the current density of 1.0 A g^-1, after 300 cycles, the capacity is 618 mA h g^-1; after 200 cycles under the current density of 2.0 A g^-1, the reversible specific capacity can still maintain 551 mA h g^-1.